The two runways that run in parallel are too close to each other to land side-by-side in bad weather (because they only allow using Visual aka VFR landings).
"SFO operates on two sets of parallel runways. On fair weather days, SFO can accommodate approximately 60 arrivals per hour. During periods of low visibility, current FAA safety regulations allow aircraft to arrive side-by-side only if runways are at least 4,300 feet apart."
"SFO operates on two sets of parallel runways. On fair weather days, SFO can accommodate approximately 60 arrivals per hour. During periods of low visibility, current FAA safety regulations allow aircraft to arrive side-by-side only if runways are at least 4,300 feet apart."
https://www.flysfo.com/about/airport-operations/policies-reg....